This research proposal consists of the following projects: 1) a study of the possible role of cAMP and calcium in the autoregulation of insulin and glucagon secretion by perifused pancreatic islets of insuloma-bearing hamsters, obese hyperglycemic mice and control animals; 2) an attempt to prepare relatively pure suspensions of A and B cells for the purpose of studying their secretory activity; 3) fractionation and physiologic role of glucagon-like immunoreactive materials from the intestinal mucosa and, in particular, their effect on food intake; 4) a study of the role of salivary glands and kidney in the regulation of serum glucagon level in normal, depancreatized and eviscerated rats; 5) role of glucagon insufficiency in human hypoglycemic syndromes; and 6) a study of the possible insulotrophic action of the anterior pituitary in animals with hypertrophic islets due to sulfonylurea treatment.